Community Cloud is a social platform from Salesforce.com that is designed to connect and facilitate communication among an organization's employees, partners and customers.
Community Cloud employs Salesforce's Chatter social CRM platform for chat and screensharing, allowing users to exchange data and images in real time throughout an ongoing conversation. The platform supports customer relationship management (CRM) and provides channels for customers to find information and communicate with other customers. The console also includes a "Buy" button to enable e-commerce.
Employees can use the platform for many types of workplace interactions, including troubleshooting, human resources management (HRM) and help desk communications as well as collaboration among geographically dispersed teams. Management can use it to communicate more efficiently with channel partners and other external parties.
In a generic context, a community cloud is a Multi-tenant infrastructure that enables collaboration among several organizations from a specific group with common computing concerns such as regulatory compliance, audit requirements or performance requirements.
See a brief introductory video about Community Cloud: